One big reason India is beefing up its arsenal: China.
"It goes without saying that India must be seriously concerned with the rise of China's strategic power, including its military and economic power," says Ashwani Kumar, member of parliament from India's ruling Congress party. "India has consistently opposed an arms race—but India will not be found wanting in taking all measures necessary for the effective safeguarding of its territorial integrity and national interests."
From the Arabian Sea to the Pacific Ocean, countries fearful of China's growing economic and military might—and worried that the U.S. will be less likely to intervene in the region—are hurtling into a new arms race.
The buildup is unfolding as the world's military balance appears to be shifting in tandem with its economic balance. China is beginning to build a military to match its powerful economy. This is happening as the U.S. and its staunchest allies, including Britain, are looking at flat or falling military spending—and as Russia is struggling to revive its armed forces in the post-Soviet era.
China is still far from challenging the U.S. for global military supremacy. But its recent actions have countries in the region planning for a much different future.
In Australia, a report published Monday by an influential defense think tank concludes that the China threat has sparked an "urgent need to refocus" military development "to offset and deter the rapidly expanding People's Liberation Army." The report by the Kokoda Foundation, prepared with input from senior defense officials, says Australia "cannot overlook the way that the scale, pattern and speed of the PLA's development is altering security in the Western Pacific."
Xinhua/ZUMA PressSoldiers in India
"This is potentially the most demanding security situation faced since the Second World War," says Ross Babbage, author of the report. "This is not Mickey Mouse. This is dead serious stuff."
In Washington, a new "National Military Strategy" released Tuesday says that the U.S. "strategic priorities and interests" will increasingly be in the Asia-Pacific region. The Pentagon strategy paper says the U.S. intends to "invest new attention and resources" in South and Southeast Asia, and will look for new ways to increase cooperation among American allies as they build up their own military power.
"We remain concerned about the extent and strategic intent of China's military modernization, and its assertiveness in space, cyberspace, in the Yellow Sea, East China Sea, and South China Sea," the Pentagon paper says.
Both the U.S. and Australia have expressed particular concern about the vulnerability of military computer systems to cyberattack by China. The Australian report warned that in a crisis, such systems might not be secure.
Getty ImagesA helicopter in a South Korean live-fire exercise
China has said that its military modernization is not directed at any other country, and that its military spending is much lower than that of the U.S. "We do not engage in an arms race. We are not a military threat to any country," said President Hu Jintao during a visit to the U.S. last month. "China will never seek to dominate or pursue an expansionist policy."
The region's newly bristling arsenals have stoked concerns that more powerful militaries could lead nations to pick fights over long-held territorial grudges, threatening to destabilize an area whose waters carry much of the world's cargo containers and oil.
"Little incidents could easily escalate into bigger incidents, and then little nasty wars," says Siemon Wezeman, a senior fellow at the Stockholm International Peace Research Institute, which tracks defense spending.
China, to be sure, isn't the only catalyst for the arms buildup. Many Asian militaries delayed modernizing their armed forces because of the regional financial crisis in the late 1990s. Some countries are worried about threats from Islamist or separatist insurgencies. Others fear hostilities with longtime foes, such as India with Pakistan, and South Korea with North Korea.
But China's buildup looms large. China's total defense spending was $78 billion in 2010, up from $17 billion in 2001, according to government reports. Western defense officials say those totals don't include arms imports. The U.S. Defense Department has estimated that China's total military-related spending in 2009 was $150 billion.
Getty ImagesCambodian military police
China doesn't disclose details about arms purchases. Figures made public by the Russian government indicate that China spent more than $17 billion on Russian arms imports between 2001 and 2010. Adding that figure to Chinese spending on domestic-arms procurement, Western defense experts estimate that China has spent about $150 billion on new weapons over the past decade.
China's first aircraft carrier, a diesel-powered vessel, is expected to be deployed this year or next. A prototype of a new J-20 stealth jet fighter—it appears designed to rival the U.S. F-22—made its first test flight on Jan. 11, just hours before U.S. Defense Secretary Robert Gates met in Beijing with President Hu to mend frayed relations.
The U.S., for its part, announced Jan. 6 that it would cut defense spending by $78 billion over the next five years. For the fiscal year ended in September, Congress appropriated $531 billion for the armed forces, not including costs related to the wars in Afghanistan and Iraq. Pentagon officials contend they will continue to invest in new technologies intended to counter such Chinese advances as antiship ballistic missiles.
Since World War II, America's allies in the Asia-Pacific region have counted on the U.S. to provide a security umbrella.
"Until recently, countries in the region would expect U.S. carriers to arrive in the event of a regional conflict," says Mr. Wezeman of the Stockholm peace institute. "Clearly some countries will soon start to think: 'Is the carrier really coming?'"
Sipa PressA Vietnamese military parade
Pentagon officials say the U.S. remains fully committed to security in the region. "We will continue to maintain the military strength necessary to protect our interests, defend our allies and deter potential adversaries from acts of aggression and intimidation," says Michael Schiffer, the deputy assistant secretary of defense for East Asia. The U.S., he adds, doesn't view China as an adversary.
A region-wide submarine-buying binge shows the extent to which smaller nations are moving to bolster their defenses. Compared with aircraft carriers and other large vessels, submarines are relatively cheap. Just the suspicion that submarines are patrolling can keep hostile navies at bay. They're also considered the best weapon to counter another sub.
China has about 62 subs now and is expected to add 15 in coming years, according to the U.S. Office of Naval Intelligence. India, South Korea and Vietnam are expected to get six more subs apiece by 2020. Australia plans to add 12 over the next 20 years. Singapore, Indonesia and Malaysia are each adding two. Together, the moves constitute one of the largest buildups of submarines since the early years of the Cold War. Asian nations are expected to buy as many as 111 subs over the next 20 years, according to AMI International, which provides market research to governments and shipbuilders.
AFP/Getty ImagesMalaysia's first submarine
India had long focused its military planning on Pakistan, its foe to the northwest, and Pakistan-based militants remain a major concern. India also has feuded with China for years over the border they share in the Himalayas, where China continues to claim land that is now governed by India.
But India now is growing more worried about China's potential influence over key shipping lanes. Beijing has been financing and building ports in Pakistan, Sri Lanka and Bangladesh—analysts have dubbed it China's "string of pearls" strategy for the Indian Ocean. China's goal, in part, is to secure sea lanes for its energy and mineral supplies from the Middle East and Africa, which must pass through the Indian Ocean and the Straits of Malacca, a shipping bottleneck in Southeast Asia. Like the rising powers of previous centuries—Great Britain, Spain, Portugal—the Chinese are building up their military power to ensure access to key natural resources.
India sees that as a threat. "India's lifeline of oil comes from far-off places," says Sureesh Mehta, former chief of the Indian navy and currently India's high commissioner to New Zealand. "There are times when it may need protection."
India is the fourth-largest consumer of oil in the world, and it relies on crude shipments from Middle Eastern countries including Saudi Arabia and Iran. It also imports large amounts of coal from Indonesia and Australia.
The Andaman and Nicobar Islands, a remote Indian archipelago in the Bay of Bengal about 745 miles off India's southeastern coast, has been buzzing with military activity as India bolsters its maritime defenses. The cluster of 572 islands lies just 175 miles south of mainland Myanmar, a close ally of China.
The navy controls half the port area of the territory's capital, Port Blair. The air force takes over the airport every afternoon, and it is lengthening several airstrips on the islands to handle night landings by fighter jets—a critical capability given that India only has one aging aircraft carrier in operation.
India's defense budget, which is roughly $32 billion for the year ending March 31, has increased 151% in the last decade. The government expects military spending to grow at about 8.33% annually in coming years.
Associated PressAustralian troops next to a C130 transport plane
The new Scorpène submarines, which can stay submerged for about a week, are being built with technology from France's state-owned DCNS for an estimated total cost of $4.6 billion.
India's shopping list extends far beyond subs. It purchased eight maritime-reconnaissance and antisubmarine aircraft from Boeing Co. for $2.1 billion in 2009, and the government recently approved an order for another four, says an Indian navy spokesman. The goal is to upgrade India's snooping capabilities and replace outdated Russian planes.
"This really gives them strategic reach in the Indian Ocean," says Vivek Lall, vice president in charge of Boeing's defense, space and security operations in India.
Boeing and several other aerospace firms are also in the running for an estimated $10.5 billion contract for 126 fighter jets, India's largest-ever defense order. "It's an unsaid thing, but clearly China is a big issue," says Mr. Lall.
Not many countries have benefited more from China's economic rise than Australia. China is its largest commercial partner. It buys enormous amounts of Australian coal and iron ore, which has fueled a natural-resources boom.
But that hasn't blunted concern that China's military buildup is a threat to Australian security. The report published Monday says China is close to attaining enough military muscle to deny the U.S. and allied forces access to much of the Western Pacific rim.
"The assumption that U.S. and allied naval surface vessels can operate with high security in all parts of the Western Pacific is no longer valid," the report said. U.S. aircraft carrier strike groups, it said, are becoming "increasingly vulnerable" to Chinese surveillance and weaponry up to 1,200 nautical miles from China's coast.
Mr. Babbage, author of the report, contends that Australia can no longer afford to maintain a military focused mainly on participating in peacekeeping operations, as it is doing in East Timor, and on training foreign military forces, as it is in Afghanistan.
Australia's planned $279 billion of military spending over the next 20 years will fund the biggest expansion of its military since World War II.
The report touches on a development that is especially worrisome to nations that host permanent U.S. military bases, such as Japan and South Korea. It says China is fielding ballistic and cruise missiles capable of destroying U.S. bases in Guam, Japan and elsewhere "within a few hours."
In December, Japan overhauled its defense guidelines, drawn up in the Cold War and directed principally at the Soviet Union, to focus more on China. The new guidelines call for spending as much as $284 billion between 2011 and 2015 to modernize Japan's Self-Defense Forces. Japan proposed deploying more U.S. Patriot missiles, prompting China to protest that such a move would trigger a regional arms race.
South Korea is worried about China's continued support for North Korea, and that growing Chinese military power will limit U.S. capacity to intervene if war breaks out on the Korean peninsula. In 2006, South Korea launched a 15-year military-modernization program projected to cost about $550 billion, with about one-third slated for arms purchases. The program has since been reviewed after two attacks on the South by the North last year. Military analysts expect South Korea to spend more on conventional weapons designed to defend it against the North, including subs, destroyers, F-15 fighter jets and possibly F-35s.
Vietnam and China, once steadfast allies against the U.S, are now feuding over Chinese territorial claims in the oil-and-gas-rich South China Sea. Vietnam doesn't have an economy or budget big enough to go toe-to-toe with China procuring weapons. In lieu of a big arms buildup, it is opening up a prized military asset, its deep-water port in Cam Ranh Bay, in the hopes that foreign navies will steam into the South China Sea and help secure the region's shipping lanes.
"Offering Cam Ranh Bay to foreign navies is a master stroke," says Carlyle Thayer, a professor at the Australian Defence Force Academy at the University of New South Wales. "It will attract precisely those navies that can be expected to keep China's naval ambitions in check."
—Julian E. Barnes, Patrick Barta and Tom Wright contributed to this article.Write to Amol Sharma at Amol.Sharma@wsj.com, Jeremy Page at Jeremy.Page@wsj.com, James Hookway atJames.Hookway@wsj.com and Rachel Pannett at Rachel.Pannett@dowjones.com